Flexible conduit



June 2, 1931. w 1,808,204

FLEXIBLE counuu Filed March 7, 1929 WITNESSES I N VEN TOR:

A TTORNEYS.

Patented June 2, 1931 UNITED STATES.

PATENT OFFICE JOHN H. BROWN, 01 MINNEAPOLIS, MINNESOTA, ASSIGNOB TO KEASBEY & MATTISON COMPANY,'OF AMBLEB, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA FLEXIBLE CONDUIT Application filed March 7,

This invention relates to conduits useful for example with automobile heating appliances to conduct heated air from the exhaust manifolds of the engines to radiators 5 or registers within the bodies of the vehicles.

In connection with conduits useful as above indicated and for similarpurposes, I aim to secure the advantages of strength, flexibility and ready adaptability inherent to spiralized 1o metallic tubing by employing the same as a core in conjunction with a covering of thermo insulation for oifsetting heat losses through conduction and radiation; and to attain the foregoing desideratum with cals'pacity of the covering to adapt itself readily to the flexing of the core, notwithstanding firm and eifective attachment to the latter.

The accompanying drawing is a fragmentar view showing my improved conduit partly 1n elevation and partly in section.

In carrying out this invention, I employ asa core for m improved conduit, flexible tubing 1 prefera 1y of a well known commercial kind fabricated through spiral curling of strip metal with incidental interlocking of the contiguous strip edges; and build around such a tube a thermo-insulate covering 2. As shown, this protective covering 2 comprises an inner layer 3, and an outer layer or jacket 4. The inner layer 3, I form by closely and tightly winding about the metallic core tube 1, com aratively thick cordage of twisted asbestos fi re or thelike ordinaril known in the art as wick acking. Al though I have shown the cor age layer 3 as wound in a direction counterwise to the turns of the spirals of the core tube, 1, it may, if

1929. Serial No. 845,042.

outer layer 4, and b reason of the fact that the cordage of the ayer 3 is wound on the metallic bore 1, the covering 2 obviously adapts itself readily to flexure of the conduit witllifout tendency to disintegrate or to detach itse Having thus described my invention, I claim:

1. A flexible conduit comprising a tubular core of spirally curled strip metal; and a covering including a wound on thickness of comparatively heavy thermo-insulate cordage, with an outer retaining jacket, also of thermo-insulate material, both capable of adapting themselves to the flexing of the metallic core.

2; A flexible conduit com rising a tubular core of spiralliv curled strip metal; and a covering inclu ing a wound on thickness of comparatively heavy thermo-insulate cordage, and a braided thinner outer retaining jacket, both capable of adapting themselves to the flexing of the metallic core.

3. A flexible conduit comprising a tubular core formed from spiralized strip metal having the contiguous edges interengaged; a cov ering layer of relativel heavy thermo-insulate cordage; and a braided thinner outer retaining jacket, said corda e layer and *outer covering both capable of a apting themselves to flexing of the metallic core.

In testimony whereof, I have hereunto signed my name at Minneapolis, Minnesota, this 28th day of February, 1929.

' JOHN H. BROWN.

desired or found more convenient inpractice,

be wound in the same direction as the tube spirals. The outer retaining jacket 4 may be very much thinner than t e inner cordage la er 3 and formed either by winding on as tape or yarn of lighter figs than the corda 3, or in the manner ustrated as a brai ed or woven fabric. The jacket 4, it will be seen serves as an efiective retaining means to hold the inner insulate thickness 3 intact and in close embrace about the tubular metallic core 1.

By virtue of the yielding texture of the 

